Auto complete nopCommerce:SimpleTextBox

Hi,

I am trying to modify address user controls to accept addresses from popup window.
It is ok in customer Info page because it uses generic asp.net text box control. But I can't make it work in the Customer addresses page.
In customer addresses page,
1. I disabled (asp.net:text box doesn't work if set to read only) zipcode and address 1 (hold state, city and suburb). Shoppers can't make any entries except selecting one address from popup up window.
2. Pop up window will fill the state, city and suburb if one address selected from the popup window.
   myElement = document.getElementById('<%= txtZipPostalCode.ClientID %>' + "_txtValue");
        if (myElement != null && myElement.type == "text") {
            {
                alert("this");
                myElement.value = zipcode;
            }
        }
3. I enter detail address into address2
4. Press 'Update Address' button
5. It always saves old state, city and suburb except for address2 which is enabled and writable.

Disabled asp.net textbox works fine but nopCommerce:SimpleTextBox doesn't.
Could you anyone please help me how to modify nopCommerce:SimpleTextBox to accept values inserted by code?

Thanks